1. Field of the Invention
The present invention relates to safety eyeglasses having side shields capable of protecting the eyes of a wearer from foreign substances in work environments, and more particularly, to safety eyeglasses with side shields formed from a moldable plastic that is integrally joined to metal temples of an eyeglass frame.
2. Background of the Related Art
As is well known, in certain working environments involving grinding operations or the handling of particulate substances, there is a possibility of foreign substances striking the eyes of an eyeglass wearer through the sides of the eyeglasses, thereby causing injury or irritation to the eyes and the surrounding skin. To prevent such problems, side shields are attached to the temples of the eyeglasses.
Such side shields typically have a length of about 5 cm extending from the hinge connection between the side of the eyeglasses frame toward the end portion of the temple that rests on the wearers ear, and are often made of a transparent synthetic resin material so as not to interfere with peripheral vision. They are generally mounted onto the eyeglasses temples in such a way as not to interfere with the folding of the temples. When the temples of the eyeglasses frame are made of a synthetic resin, the side shields may be formed as part of the temple in a one-step molding process. However, when the eyeglasses frame is made of metal in order to provide for a more stylish appearance, or to accommodate prescription lenses, such transparent, synthetic resin side shields are separately fabricated.
Side shields for safety eyeglasses having metal frames are either detachably or permanently connected to the metal temples. Detachable side shields may be designed to accommodate either a number of different types and sizes of metal eyeglasses frames, or they may be custom designed to fit a specific frame. Because of the broad variation in style, shape and temple dimensions of metal eyeglasses frames, it is difficult to design a “one size fits all” type side shield that detachably mounts securely on the temples all metal frames without having either a large, unsightly overlap between the side shield and the hinge portion of the frame, or a safety-compromising gap between the side shield and the frame. Even when such side shields are custom-designed to fit a particular type of frame, they must also be designed so that the forces associated with their installation or removal are relatively low, since many metal frames are relatively fragile, and are prone to bending or breakage and subjected to the pushing and pulling necessary for detachable operation. Finally, since many workers simply provide for themselves separate safety eyeglasses for use in jobs or other specialized environments requiring such eyeglasses, the detachable feature of such side shields often goes unused.
While the provision of permanent side shields that are custom designed with specific shape of a particular eyeglasses frame solves some of the aforementioned problems, other problems remain. For example, any locking mechanism that is capable of reliably securing the side shields onto the metal temples of a frame with a minimal amount of force requires small and accurately made components, such as the combination of a precision-made locking protrusion and complementary groove between the side shields and the temples. To avoid the expensive machining associated with small locking components, fasteners such as rivets and screws have been used in the prior art. Unfortunately, such fasteners require the provision of small precision holes in the metal temples which are time consuming to manufacture and to mate with the fasteners, and which also provide points of structural weakness within the temples. Of course, such problems might be reduced by widening the temples where they connect to the side shields in order to simplify the connecting process. However, such an approach requires the custom-manufacturing of the temples for a given type of eyeglass frame, and impedes peripheral vision.
Clearly, what is needed is technique for easily and permanently attaching transparent resin side shields onto the temples of metal eyeglass frames which does not require a widening or other custom-manufacturing of the temples of such frames in the area of side shield connection, and which is easily applied to a broad range of presently existing shapes, styles and temple dimensions. Ideally, such a technique would securely mount the side shields onto the metal temples for the lifetime of the frames without slippage or disconnection. Finally, it would be desirable if such a technique required a minimum amount of manufacturing steps and precision machining in order to minimize the cost of application.